Retiring 2d, awt, beans, sound and swing mailing lists on 30th September 2021

[Philip Race]

Since :
1) The old client groups mailing lists were consolidated into 
client-libs-dev at openjdk dot java dot net [1],
including subscribing all subscribers to the old invividual lists to the 
new consolidated list, and
2) The skara github tooling has also migrated to that new list and
3) Folks are already using the new list for questions etc

Then :
I think it is time to plan the retirement of all the old lists :
2d-dev [2], awt-dev [3], beans-dev [4], sound-dev [5], and swing-dev [6]

Accordingly I propose that these five old lists become archived and 
read-only as of 12pm PDT 30th September 2021
and will ask the mail server adminstrators to plan to implement this at 
that time.

I will also forward this information to each of those individual lists.

-Phil Race
Client Libs Group Lead.

[1] https://mail.openjdk.java.net/mailman/listinfo/client-libs-dev
[2] https://mail.openjdk.java.net/mailman/listinfo/2d-dev
[3] https://mail.openjdk.java.net/mailman/listinfo/awt-dev
[4] https://mail.openjdk.java.net/mailman/listinfo/beans-dev
[5] https://mail.openjdk.java.net/mailman/listinfo/sound-dev
[6] https://mail.openjdk.java.net/mailman/listinfo/swing-dev